Insulated and refrigerated containers and dry van trailers are extensively used internationally. The interior walls of these containers are often protected by a lower scuff secured to an upper liner. The lower portions of the container typically experience far more wear and abuse than the upper portions, so the scuff typically has a more resilient, thicker construction than the liner.
Increased energy costs and environmental requirements have caused thermoplastic non-metallic composite scuffs and liners to become more widely used due to their light weight, good shock resistance, wear resistance and low maintenance costs. These thermoplastic non-metallic composite scuffs and liners have become the first choice for insulated, refrigerated, and dry freight transportation vehicles. The non-metallic scuffs and liners are typically secured together by lap fusion welding using an ultrasonic welding process. FIG. 1 illustrates a prior art example of a panel 10 sonically lap welded to a sheet 15 from U.S. Pat. No. 7,829,165 issued to Grandominico.
Based on the expected wear patterns of the end user, container manufacturers vary both the thicknesses and heights of the liners and scuffs, which often requires the manufacturer to purchase a variety of non-metallic scuffs which have different dimensions integrated with the linings. While some variations of scuff and liner are typically used, there are other combinations that are rarely used. This forces manufacturers to store large quantities of scuff and liner combinations, leading to inventory management, purchasing, and daily material maintenance problems. To avoid storage costs, the manufacturer may order or produce smaller quantities of the scuff and liner combinations, but then the manufacturer loses certain economies of scale resulting in higher prices per unit.